Cylindrical electrochemical cells

ABSTRACT

Cylindrical cells each comprising a metal container for cell contents and sheathed by plastic material, which sheath is covered at least on the cylindrical part of the container by a metallic armoring jacket are disclosed. This jacket is formed from a rolled metallic sheet, whose adjoining edges do not overlap. The jacket at its lower end at least is tightened about the plastic sheath by means of a compressive metallic ring having substantially an L cross-section. In a modified form a second similar ring may be applied at the upper end of the jacket. Jackets of simple structure, requiring no complex material for mounting in place on the plastic sheathed container with no important variations in the dimensions of cells provided with such armoring jackets over cells not having them result.

United States Patent 1191 Jammet 1 1 Jan. 7, 1975 1 CYLINDRICALELECTROCHEMICAL 3,622,392 11/1971 Larsen et al. 136/107 CELLS 3,655,4494/1972 Yamamoto et a1. 136/107 [75] Inventor: Jean Jammet, Poitiers,France [73] Assignee: Saft-Societe Des Accnmulateurs Fixes Et DeTraction, Romainville, France [22] Filed: Nov. 8, 1973 {21] Appl. N0.:414,085

Related US. Application Data [63] Continuation of Ser. No. 237,486,March 23, 1972.

[30] Foreign Application Priority Data Mar. 26, 1971 France 71.237486[52] US. Cl. 136/107, 136/175 [51] Int. Cl. H01m 21/00 [58] Field ofSearch 136/107, 102, 106, 175, 136/176 [56] References Cited UNITEDSTATES PATENTS 3,168,420 2/1965 Jammet 136/107 3,463,669 8/1969 Jammet3,573,990 4/1971 Tsuchida et al. 136/107 Primary Examiner-Winston A.Douglas Assistant ExaminerC. F. Lefevour Attorney, Agent, or Firm-Kenyon& Kenyon Reilly Carr & Chapin [57] ABSTRACT Cylindrical cells eachcomprising a metal container for cell contents and sheathed by plasticmaterial, which sheath is covered at least on the cylindrical part ofthe container by a metallic armoring jacket are disclosed. This jacketis formed from a rolled metallic sheet, whose adjoining edges do notoverlap. The jacket at its lower end at least is tightened about theplastic sheath by means of a compressive metallic ring havingsubstantially an L cross-section. In a modified form a second similarring may be applied at the upper end of the jacket. Jackets of simplestructure, requiring no complex material for mounting in place on theplastic sheathed container with no important variations in thedimensions of cells provided with such armoring jackets over cells nothaving them result.

11 Claims, 3 Drawing Figures PATENTED JAN 7 i975 SHEET 10F 3 FIG/IFATENTEDJAN H915 3,859,137

P ATENTEI] JAN 7 I975 SHEET 3 OF 3 FIG.3

CYLINDRICAL ELECTROCHEMICAL CELLS RELATED APPLICATIONS This is acontinuation, of application Ser. No. 237,486 filed Mar. 23, 1972.

BRIEF SUMMARY OF INVENTION The invention relates to cylindrical drycells and more particularly those comprising a metallic container whichserves as the external electrode, the internal electrode being aconducting rod, for example, of carbon, the container and its cellcontent being contained within a thin coating sheath of plasticmaterial, whose lower end is folded around onto the bottom of saidcontainer, the said sheath being covered, at least on its cy lindricalportion, by a metallic armoring jacket.

In cases where the metallic container is of the consumable type, it isprovided advantageously at its lower end with a metallic cup that coversthe bottom of the container and preferably is fastened in place bycompressing deformation of the side wall of the cup.

The metallic jacket, which constitutes what will be called the armor ofthe cell, serves to prevent the swelling of the cell container,particularly at the time of a very quick discharge of the cell becauseof the gases that are then produced.

It is actually known, more particularly from French Pat. No. 1,593,630filed Nov. 13, 1968 (No corresponding U.S. application) of providingsuch armoring jackets by use of metallic tubes.

These tubes can have such an internal diameter than the cell ensembleincluding its metal container and other components must be forciblyintroduced into the tube or better the tube may have a diameter slightlylarger than that of the cell ensemble and after introduction, the tubediameter may be reduced in diameter by appropriate compression totightly engage the ensemble.

Such armoring jackets in the form of tubes are inconvenient because ofrelatively precise dimensions. Their use, moreover, is not veryeconomical.

A solution has been suggested which is to provide these armoring jacketsby use of rolled metallic sheets whose edges are joined by hooking andcramping the interlocked hooked edges. However, this procedure requiresuse of a complex tool and complex procedure.

In addition, because of the methods of hooking used and especiallybecause of the superposition of the hooked edges of the rolled sheetforming the jacket, the mounting of such a jacket effects an increase inthe diameter of the cell which can be calculated as being about 5 to 6times the thickness of said sheet.

It is essential that the cells present normalized or standardizeddimensions, especially relative to their final diameters. The presenceof such jackets thus forces the manufacturer, in order to comply withrequired tolerances, to diminish the diameter of the cell ensemblecomposed of the other components. This, in practice, results in adecrease in cell capacity.

Therefore, the use ofjackets can cause a loss of 7 to 9% of volume ofthe depolarizing mass inside cylindrical cells of type R-ZO and of 10 to12% inside cells of Type R-l4.

Furthermore, assuming that these cells, deprived of their armoringjackets, will not satisfy the conventional standards concerning theirdimensions, this will force the manufacturer to maintain for each suchcell two scales of production, one applying to armored cells. the otherto unarmored cells.

This invention has for an object and feature especially a remedy tothese inconveniences.

The subject matter of this invention is the provision of a cylindricalcell comprising a metallic container which serves as the externalelectrode, the internal electrode being a conducting rod, e.g. ofcarbon, the ensemble including the container being contained within athin sheath of plastic material, said sheath being covered at least inits cylindrical part by a metallic armoring jacket, characterized by thefact that said jacket is made of a rolled sheet, with closely adjacentedges that do not overlap, the lower part of said jacket, at least,being tightened onto the plastic sheath by means of a metallic ring withL shaped cross-section. This results in bringing the edges of the sheetinto close or abutting relationship.

According to a characteristic of this invention, said L shaped ringafter mounting is compressed so that its external diameter issubstantially equal to the internal diameter of the part of the jacketwhich it surmounts, and of substantially the same diameter as finaldiameter of the jacket adjacent the ring.

The upper end of the jacket can be folded down onto the top of theplastic sheath.

According to the invention, in another embodiment, the upper part of thejacket may be tightened against the plastic sheath by means ofa secondsimilar metallic ring located at the upper end of said jacket.

This second metallic ring after mounting can be compressed, its externaldiameter then being substantially equal to the external diameter of thepart of the jacket adjacent the end which it surmounts.

The jackets in accord with the present invention, are manufacturedsimply and economically, and do not require the use of a complexmachinery or procedure.

Since the use in a cell of the jacket according to the invention at mostrequires an increase of diameter of only twice the thickness of thesheet constituting the jacket, this thickness having, for example, thevalue of 0.2 millimeters, it is possible for each type or standard sizeof cell to require only one scale of manufacturing dimensions becausethe dimensions of the cell whether armored or not armored can satisfythe required normalized or standard conditions.

The presence of a jacket according to the invention for the same reasondoes not require the depolarizing mass to undergo a material loss ofvolume, in comparison to the maximum volume capable of being insertedinto the cell container any such loss being less than 50% of the valuesmentioned above for cells of the R2O or R-l4 type using jackets withhooked interlocked edges. 7

Also, it must be noted that the use of ajacket according to thisinvention provides an economy of sheet metal of about 10% in comparisonto that required for the jacket with hooked interlocked edges.

Other characteristics of the invention will come out from the detaileddescription which follows in conjunction with the accompanying drawingsin which:

FIG. 1 is a cross-sectional view of one embodiment of a cell embodyingthe invention;

FIG. 2 depicts schematically one mode of preparing a cell depicted inFIG. I, and

FIG. 3 is a cross-sectional view of another embodiment of a dry cellembodying the invention.

Referring to FIGS. 1 and 3, reference numeral 1 designates anagglomerated compressed depolarizer, for example, based on manganesedioxide. Reference numeral 2 designates a conducting rod, for example,of carbon, serving the role of positive electrode for the cell.Reference numeral 4 designates an electrolyte, preferably of gelatinizedtype and reference numeral 5 designates a container of zinc.

An insulating cardboard washer 6 and a Kraft paper cup 7 at the bottomof container 5 assure the centering of the just-described agglomeratedmaterial inside the container 5. A protective sealing cup 8 is providedat the bottom of cup 5 which is compressed around the periphery ofcontainer 5 adjacent its bottom.

For a better understanding of the invention, the effect of thecompressing deformation of parts has been voluntarily exaggerated in thedrawings.

Reference numeral 9 designates a thin sheath of plastic material whichhas been applied to the zinc container after it is filled with cellcomponents above described.

The lower end portion of the sheath 9 is advantageously indented and itsedge bent around and about the bottom of a sealing cup 8.

The reference numeral 11 designates a tubular metallic jacket which,according to the invention, consists of a rolled, metallic sheet whosefacing end edges do not overlap.

This jacket 11 has a straight edge portion at its lower end which iskept tightly compressed against the lower portion ofthe cell near thebottom by means ofa metallic ring 10 with L-shaped cross-section.

Advantageously this ring 10 is mounted over the jacket 11 and set inplace by compressing deformation. After this operation, the externaldiameter of ring 10 is equal substantially to the external diameter ofthe portion of the jacket 11 directly adjacent to it.

Sealing tightness thus is effected at the lower portion of the cell.This sealing is excellent because the lower extremity of the plasticcontainer 9 is tightly compressed between the cup 8 at the bottom of thecontainer 5 and the vertical leg of L-cross-sectioned metallic ring 10with interposition also of the extremity of ar-' moring jacket 11.

In the example of FIG. 1, the upper end of the conducting rod 2 iscovered by a metallic cup 3.

The upper extremity of the armoring jacket 11 is folded over onto thetop of the plastic sheath 9.

Advantageously, in this embodiment, the length of the upper edge ofarmoring jacket 11 is slightly larger than the length of its lower edge.

This is seen in FIG. 2 which depicts very schematically a cell similarto that of FIG. 1 before the application thereto of ring 10 with Lshaped cross-section.

In this manner, after mounting said ring 10 and deforming it bycompression, gaping of the facing edges ofjacket II is avoided in thevicinity of the upper portion of the cell. These facing edges then canbe either in abutting contact or only very slightly spaced apart, forexample, a distance of the order of but 0.1 or 0.2 mm.

The embodiment of FIG. 3 differs mainly from that of FIG. I in that theupper end portion of the jacket 11 is not folded over onto the uppertransverse portion of the plastic sheath 9 but instead it is tightenedagainst the upper periphery ofthis sheath 9 by use of a metallic ring12. This ring 12, like ring 10, is originally of L- shapedcross-section. After application of said ring 12 its horizontal leg isbent over and onto the upper transverse portion of sheath 9.

This ring after mounting about the upper peripheral portion ofjacket 9can be subjected to compressing, its external diameter after thisoperation being substantially equal to the external diameter of theupper peripheral portions of the jacket 11 adjacent to it.

Advantageously in this embodiment, some provision for reinforcement ofthe upper portion of the cell should be made so that the compression ofring 12 can be done correctly.

In the embodiment shown in FIG. 3, the upper portion of sheath 9 in thevicinity of its perimeter is thickened in its transverse portion andprovided with two practically parallel grooves 13 and 14 thus defining asort of S-formation and in which grooves respectively lie the upperextremity of container 5 and the cylindrical portion 15 of lid 16, thelatter being provided to overlie the transverse portion of sheath 9 andbe in electrical contact with the conductive rod 2.

The height of the upper extremity of container 5 engaged in the groove13 is advantageously less than that of the cylindrical portion 15 of lid16 that is engaged in the groove 14.

Optionally, the top of sheath 9 of FIG. 3 can be provided at itsperiphery with a small folding strip (not shown) serving to insulate inthe most complete manner possible the ring 12 from the lid 16.

In the embodiment depicted in FIG. 3, wherein the upper extremityofjacket No. 11 is secured by use of a compressed metallic ring 12, itis not necessary to provide different lengths at the upper and loweredges of the sheet which constitutes said armoring jacket.

In both described embodiments, the manufacturing procedure comprisesproviding cylindrical metallic cell containers, filling the containerswith requisite cell components, applying a thin plastic sheath to thefilled containers, providing a rolled thin sheet of armoring material ofsubstantially cylindrical shape but whose facing edges are spaced apartand do not overlap, mounting said rolled sheet about the plasticsheathed container, providing a metallic ring of substantially L- shapedcross-section, mounting said ring about the rolled sheet at its lowerperiphery, arid then applying compressing deformation to said ring toreduce its internal diameter thereby tightening said rolled sheetagainst the plastic sheathed container and bringing said facing edges ofsaid rolled sheet into close proximity, thus providing a completed cellhaving an armoring jacket serving to counteract swelling tendencieswithin the cell container during use of the cell.

In the second embodiment, an additional ring is similarly mounted aboutthe periphery of the rolled sheet in its upper portion and compressivelydeformed subsequent to mounting to prevent gaping of the facing edges ofthe sheet forming the armoring jacket.

In both embodiments of the invention, despite application of rings 10 or10 and 12, the cylindrical periphcries of the resulting armor jacketedcells present substantially unbroken straight longitudinal lengths.

Although specific embodiments of the invention have been described andshown, variations in procedure and structure within the scope of theappended claims are possible and are contemplated. There is nointention, therefore, of limitation to the disclosure hereinabovepresented.

What is claimed is:

l. A cylindrical electrochemical cell comprising a metal container forcontents of the cell, a sheath of plastic material surrounding saidcontainer, a metallic split armoring jacket comprising a rolled sheet ofmetal having unjoined facing axially extending edges surrounding saidsheath at least in a cylindrical container region, and a metallic ringof substantially L crosssection mounted over said jacket at at least oneend thereof and being of reduced overall internal diameter relative toinitial diameter, so as to tighten said rolled sheet around said sheathand bring said facing end edges of said rolled sheet closely togetherwithout joining them, the overall external diameters of said mountedring and the adjacent portions of said sheet not covered by said ringbeing substantially equal.

2. A cell according to claim 1, wherein said plastic sheath has aportion that spans the metal container at one end thereof and whereinsaid outer armoring jacket has one of its ends turned over said portionof said sheath.

3. A cell according to claim 1, wherein a second metallic ring ofsubstantially L-shaped cross-section is mounted over said jacket at itsother end and is also re duced in overall internal diameter to enhancetightening of said jacket around said plastic sheath.

4. A cell according to claim 3, wherein the external diameter of saidsecond metallic ring is substantially equal to that of cylindricalportions of said jacket adjacent thereto.

5. A cell according to claim 3, including a carbon rod in the contentsof said cell, a metallic cover member mounted on an end of said rod,said plastic sheath having a transverse portion underlying said metalliccover member and having a portion defining a substantial S in section,said metallic cover having a cylindrical portion engaging betweenparallel walls of the S section of said plastic sheath, and said metalcontainer having its upper end portion engaged between another pair ofparallel walls of the said S section.

6. A cell according to claim 5, wherein the upper end portion of themetal container engaged between said second pair of parallel walls ofsaid S section has less height than the cylindrical portion of saidcover engaged between said first named pair of parallel walls of saidplastic sheath.

7. A cell according to claim 5, wherein the plastic sheath is shaped toinsulate the second metallic ring from said metallic container, and saidmetallic cover member.

8. A cell according to claim I, wherein said cell includes a carbon rod,and a metallic cap mounted on an end of said rod in intimate electriccontact therewith.

9. A cylindrical electrochemical cell comprising a metal container forcontents of the cell, said container serving as negative electrodetherefor, a rod-like posi tive electrode, depolarizing material andelectrolyte within said container, a sheath of plastic materialsurrounding said container, a split metallic armoring outer jacket andcomprising a rolled metal sheet surrounding said sheath at least in thecylindrical container region thereof, said sheet having unjoined facingend edges defining an axially extending split extending substantiallythe full axial length of said rolled sheet, and a metallic ring ofsubstantially L cross-section mounted over said jacket at at least oneend thereof, said ring being reduced overall internal diameter relativeto its original dimensions so that the said unjoined facing end edges ofsaid rolled sheet that form the jacket are maintained close together andsaid split jacket tightly surrounds said sheath.

10. A method of manufacturing a cylindrical electrochemical cell toprovide an armoring external jacket therefor comprising providing acylindrical metallic cell container including requisite cell componentsand bearing an external sheath, providing a rolled split metal sheet ofsubstantially cylindrical shape with axi ally extending spaced apartfacing edges, mounting said rolled split sheet about the sheath on saidcontainer, providing a metallic ring of substantially L-shaped section,mounting said ring over the mounted rolled split sheet adjacent one endthereof and applying compressive deformation to said ring to reduce itsoriginal diameter and thereby tighten the rolled split sheet around thesheath and bring the said facing edges of said sheet closely togetherwithout joining them so as to provide the said armoring jacket.

11. A method according to claim 10, including provision of a second ringof substantially L-shaped section, mounting said second ring over saidmounted sheet adjacent its opposite end and applying compressivediametrical reducing deformation to said second ring so as also tomaintain facing edges of said sheet adjacent said opposite end closelytogether without being joined.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO.3,859,137 Dated January 7, 975

Inventor(s) n Jammet It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

In item 80 or the preamble the foreign priority data 71 237 n 6 shouldread ---71 10 809-"; In column 6, line 19, ---in- --wshoufi be insertedafter "reduced" Signed and sealed this 4th day of March 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officerand Trademarks FORM po'mso USCOMM-DC wan-P09 U.S, GOVERNMENT PRINTINGOFF ICE Ill! O-JlO-Zfll

1. A cylindrical electrochemical cell comprising a metal container forcontents of the cell, a sheath of plastic material surrounding saidcontainer, a metallic split armoring jacket comprising a rolled sheet ofmetal having unjoined facing axially extending edges surrounding saidsheath at least in a cylindrical container region, and a metallic ringof substantially L crosssection mounted over said jacket at at least oneend thereof and being of reduced overall internal diameter relative toinitial diameter, so as to tighten said rolled sheet around said sheathand bring said facing end edges of said rolled sheet closely togetherwithout joining them, the overall external diameters of said mountedring and the adjacent portions of said sheet not covered by said ringbeing substantially equal.
 2. A cell according to claim 1, wherein saidplastic sheath has a portion that spans the metal container at one endtHereof and wherein said outer armoring jacket has one of its endsturned over said portion of said sheath.
 3. A cell according to claim 1,wherein a second metallic ring of substantially L-shaped cross-sectionis mounted over said jacket at its other end and is also reduced inoverall internal diameter to enhance tightening of said jacket aroundsaid plastic sheath.
 4. A cell according to claim 3, wherein theexternal diameter of said second metallic ring is substantially equal tothat of cylindrical portions of said jacket adjacent thereto.
 5. A cellaccording to claim 3, including a carbon rod in the contents of saidcell, a metallic cover member mounted on an end of said rod, saidplastic sheath having a transverse portion underlying said metalliccover member and having a portion defining a substantial S in section,said metallic cover having a cylindrical portion engaging betweenparallel walls of the S section of said plastic sheath, and said metalcontainer having its upper end portion engaged between another pair ofparallel walls of the said S section.
 6. A cell according to claim 5,wherein the upper end portion of the metal container engaged betweensaid second pair of parallel walls of said S section has less heightthan the cylindrical portion of said cover engaged between said firstnamed pair of parallel walls of said plastic sheath.
 7. A cell accordingto claim 5, wherein the plastic sheath is shaped to insulate the secondmetallic ring from said metallic container, and said metallic covermember.
 8. A cell according to claim 1, wherein said cell includes acarbon rod, and a metallic cap mounted on an end of said rod in intimateelectric contact therewith.
 9. A cylindrical electrochemical cellcomprising a metal container for contents of the cell, said containerserving as negative electrode therefor, a rod-like positive electrode,depolarizing material and electrolyte within said container, a sheath ofplastic material surrounding said container, a split metallic armoringouter jacket and comprising a rolled metal sheet surrounding said sheathat least in the cylindrical container region thereof, said sheet havingunjoined facing end edges defining an axially extending split extendingsubstantially the full axial length of said rolled sheet, and a metallicring of substantially L cross-section mounted over said jacket at atleast one end thereof, said ring being reduced overall internal diameterrelative to its original dimensions so that the said unjoined facing endedges of said rolled sheet that form the jacket are maintained closetogether and said split jacket tightly surrounds said sheath.
 10. Amethod of manufacturing a cylindrical electrochemical cell to provide anarmoring external jacket therefor comprising providing a cylindricalmetallic cell container including requisite cell components and bearingan external sheath, providing a rolled split metal sheet ofsubstantially cylindrical shape with axially extending spaced apartfacing edges, mounting said rolled split sheet about the sheath on saidcontainer, providing a metallic ring of substantially L-shaped section,mounting said ring over the mounted rolled split sheet adjacent one endthereof and applying compressive deformation to said ring to reduce itsoriginal diameter and thereby tighten the rolled split sheet around thesheath and bring the said facing edges of said sheet closely togetherwithout joining them so as to provide the said armoring jacket.
 11. Amethod according to claim 10, including provision of a second ring ofsubstantially L-shaped section, mounting said second ring over saidmounted sheet adjacent its opposite end and applying compressivediametrical reducing deformation to said second ring so as also tomaintain facing edges of said sheet adjacent said opposite end closelytogether without being joined.